Last Friday, President Obama continued his streak of negative comments about the Keystone XL tar sands pipeline, telling a South Carolina audience that it would carry heavy Canadian oil sands whose production is "extraordinarily dirty" and that it would create safety risks by carrying the crude through agricultural land. "I haven't made a final determination on it," Obama said, "but ... we're not going to authorize a pipeline that benefits largely a foreign company if it can’t be shown that it is safe and if it can’t be shown that, overall, it would not contribute to climate change."